Corrugated deck joist

ABSTRACT

A DECK JOIST ASSEMBLY INCLUDES A CORRUGATED PANEL SERVING AS A TOP CHORD AND A BAR JOIST MEMBER HAVING A SINUOUS WEB THE PEAKS OF WHICH ARE WELDED TO THE UNDERSURFACE OF THE PANEL. RESISTANCE TO LATERAL LOAD DEFLECTION IS PROVIDED BY A PLURALITY OF TRANSVERSE RODS WELDED TO THE PANEL EITHER TO THE TOP OR BOTTOM SURFACE THEREOF AT POINTS ADJACENT THE WELDED WEB PEAKS.

Feb. 9, 1971 VAN RENSSELAER P. SAXE 3,561,184

CORRUGATED DECK JOIS'I Filed Feb. 5, 1969 FIG. 3-.

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VAN RENSSELAER P. SAXE BY M74 RNEY United States Patent Oflice 3,561,184 CORRUGATED DECK JOIST Van Rensselaer P. Saxe, 1701 St. Paul St., Baltimore, Md. 21202 Filed Feb. 3, 1969, Ser. No. 795,903 Int. Cl. E04b /23; E04c 3/20 US. Cl. 52-630 4 Claims ABSTRACT OF THE DISCLOSURE A deck joist assembly includes a corrugated panel serving as a top chord and a bar joist member having a sinuous web the peaks of which are welded to the undersurface of the panel. Resistance to lateral load deflection is provided by a plurality of transverse rods welded to the panel either to the top or bottom surface thereof at points adjacent the welded web peaks.

\ Pat. No. 3,094,813 issued June 25, 1963 which is designed to be used under the same circumstances as the present invention, that is, in steel reinforced concrete building construction. In the referenced prior patent an assembly is disclosed comprising a corrugated sheet deck which serves as the top chord member in association with a sinuous web bar joist the peaks of which project upwardly through openings in the corrugated deck and are attached thereto by welding. The labor and cost factors involved with such an assembly will be quite apparent in view of the plurality of openings that must be cut throughout the length of each corrugated panel and the subsequent multiple welding points that must be made when assembling the bar joist to the panel. Likewise, it will be appreciated that suitable jigs are necessary to support a plurality of transverse reinforcing rods which must be welded to the peaks of the bar joist projecting above the top surface of the corrugated panel in order to provide lateral load resistance.

By the present arrangement, however, an improved assembly is provided which has been found to exhibit comparable strength when considering the arrangement disclosed in my prior patent with a noticeable decrease in the labor and expense required to fabricate the assemblies. By selecting a corrugated metal deck of appropriate gauge it has been found that the openings in the deck may be dispensed with and the peaks of the sinuous web of the bar joist can be attached to the undersurface of the deck and the lateral or transverse reinforcing rods may then be welded either above or below the metal deck adjacent the peaks of the joist web. Previously, it was felt that the peaks of the joist web should extend above the metal deck in order to provide a positive interlock with the cast flooring slab subsequently poured upon the top of the assembly; however tests have shown that by the present assembly of the corrugated metal deck and bar joist suflicient strength is obtained thus precluding the requirement of any additional interlocking feature above the top surface of the metal deck. This discovery is even more readily appreciated when considering the use of flooring slabs composed of recently developed compositions. This refers particularly to the new gypsum compositions which have been found to yield properties 3,561,184 Patented Feb. 9, 1971 comparable to that of concrete from the strength standpoint and which, even more importantly, are of substantially less weight, namely, approximately two-thirds less weight than concrete. It is expected that the substitution of this improved gypsum for the heretofore used concrete will become increasingly popular in the specifications of future building construction not only from the standpoint of the weight saving but also in view of the far superior sound deadening properties.

Accordingly, one of the primary objects of the present invention is to provide an improved deck joist comprising a top chord of corrugated sheet metal and an integrated bar joist having a minimum overall height.

Another object of the present invention is to provide a corrugated deck joist including a sinuous bar web having its peaks attached to the undersurface of the corrugated sheet.

Still another object of the present invention is to provide a minimum height deck joist including integrated sheet metal panels and bar joists which are provided with additional lateral load resistance by means of transverse rods placed either above or below the sheet metal deck at points adjacent the peaks of the bar joist web.

With these and other objects in view which will more readily appear as the nature of the invention is better understood the invention consists in the novel construction, combination and arrangement of parts hereinafter more fully described, illustrated and claimed.

A preferred and practical embodiment of the invention is shown in the accompanying drawing, in which:

FIG. 1 is an end elevation, partly in section, and illustrates a plurality of laterally joined deck joist assemblies according to the present invention.

FIG. 2 is a partial top perspective view of the present invention.

FIG. 3 is a partial side elevation of the structure disclosed in FIG. 1.

Similar reference characters designate corresponding parts throughout the several figures of the drawing.

The present invention will be understood to comprise a plurality of deck joist assemblies, generally designated 1, adapted to be supported in a spanning relationship between pairs of laterally spaced apart support beams 2. Each joist assembly 1 includes a corrugated sheet metal panel 3 having its corrugations extending longitudinally of the panel, which panel serves as the shallow top chord of the completed deck joist assembly. The thickness of the metal used for the panel .3 as well as the vertical height between the valleys 4 and crests 5 of the panels will be determined by the specifications set forth for the particular job requirement at hand. It will be appreciated that the basic configuration of a corrugated panel imparts thereto a significant degree of longitudinal stability; however the construction of a bar joist utilizing the panel 3 as the top chord member thereof will be understood to provide an extremely high degree of both longitudinal and lateral stability to the completed joist assembly.

Except for the top chord member 3 the joist will be seen to be constructed of rod or bar stock, this stock being the most economical and yielding the greatest strength-toweight ratio, although quite obviously other materials may be used, such as angle bars, etc. The web 6 of the joist comprises a serpentine or sinuous bar having alternating top peaks or arches 7 and bottom valleys 8 each disposed respectively in common horizontal planes parallel to one another. The web valleys 8 are in turn each joined to a longitudinal bottom chord 9 extending substantially the greater length of the joist assembly 1 while the top portion of each of the web peaks or arches 7 are welded to the undersurface of the corrugated panel 3, preferably at points immediately adjacent the crest 5 of the panel. From a point adjacent the endmost web portion 3 6 a diagonal member 10 extends upwardly and outwardly to a point short of the end of the panel to define a bar end portion 11 parallel to the running length of the corrugations and likewise preferably welded to the undersurface of the panel 3 at a point immediately opposite the top of the corrugation crest 5.

Resistance to lateral load deflection is imparted to the deck joist assembly by means of a plurality of transverse rods 12, one of which is provided for each of the web peaks 7 and the length of which will be understood to be substantially the width of each corrugated panel 3. As disclosed most clearly in FIG. 2 these rods 12 are positioned in a straight line manner transverse to the longitudinal corrugations of the panel 3 and are spot welded to the juxtaposed portion of each web peak 7 as well as any desired number of the valleys 4 of the panel which engage the juxtaposed rod 12. As illustrated in the righthand joist assembly 1 of FIG. 1 the transverse rods 12 may also be located upon the top surface of the corrugated panels 3, in which case there will be no direct weld connection between these rods and the sinuous web 7, although most preferably the rods 12 will be welded to the top of the juxtaposed crests 5 at a point overlying the web peaks 7 located on the undersurface of the panel 3.

Deck joists according to the present invention represent a substantial savings in quantity of steel over other installations utilizing regular bar joists which usually incorporate a pair of angle bars or a fiat U channel for the top chord. This is due to the use of the corrugated panel 3 which is made of a steel having a higher compression value than that of the usual angle members of a regular bar joist. Thus considerably less pounds of steel are required with the instant assembly to support a fixed load than with other bar joist assemblies. To take full advantage of the load bearing capabilities of the corrugated panel 3, the transverse rods 12 are employed, and through the welding of the rods 12 to the adjacent valleys 4 or crests 5 serve to laterally distribute the load forces from each web peak 7 such that the adjacent panel corrugations act as a unit. Considering the maximum design requirements it has been determined that the two corrugations either side of each peak 7 should be welded to the bar 12. Tests have also shown that panel corrugations having depths between /z1" will meet all design requirements according to the present invention.

The above described joist assemblies are fabricated prior to delivery to the construction site whereupon each assembly is individually hoisted into position spanning a pair of spaced apart support beams 2. Any number of the joist assemblies may then be placed in side-to-side adjacent relationship with the adjoining panel edges 3a in an overlapping disposition as shown in FIG. 1 prior to a nominal tack welding of these overlapping edges 3a to retain the adjacent assemblies in this position during formation of the floor slab S thereupon.

When the cast in situ slab S is formed upon the top surface of the positioned joist assemblies 1 it will be readily appreciated that relative shifting between the slab and the joist assemblies will be precluded in view of the sinuous or corrugated interface between these two components and in the case of a joist assembly provided with the transverse rods 12 upon the top surface of the panels 3 even more resistance to shifting is provided in view of the additional interlocking relationship between the slab S and joist assemblies 1.

I claim:

1. A deck joist assembly comprising a top chord including a panel of corrugated metal having a plurality of adjacently disposed alternate crests and valleys each axially extending longitudinally thereof, a vertically undulating bar web disposed below said panel and having alternate peaks and valleys extending substantially the length of said panel, each of said web peaks attached to the undersurface of a crest of said panel at a point spaced inwardly from the two lateral edges of said panel, and transverse rods attached to said panel at points adjacent said web peak attachments to said panel.

2. A deck joist assembly according to claim 1 wherein said transverse rods pass beneath said web peaks and are attached to the bottom of said panel valleys.

3. A deck joist assembly according to claim 1, wherein said transverse rods are attached to the top of said panel crests.

4. A deck joist assembly according to claim 1, wherein said panel corrugations are of a depth between /21.

References Cited UNITED STATES PATENTS 1,908,663 5/1933 Gentz 52-690 1,872,984 8/1932 Land 52--336 2,055,701 9/1936 Palmer 52-335 2,639,010 5/1953 Weber 52336 3,094,813 6/1963 Saxe 52336 HENRY C. SUTHERLAND, Primary Examiner I. L. RIDGILL, JR., Assistant Examiner U.S. Cl. X.R. 52336, 723 

